public class e4_8 {
  public static void main(String args[]){
     Circle circle = new Circle();
     circle.setRadius(10);
     Circular circular = new Circular ();
     System.out.println("circle的引用："+circle);
     System.out.println("圆锥bottom的引用:"+circular.bottom);
     circular.setHeight(5);
     circular.setBottom(circle);
     System.out.println("circle的引用:"+circle);
    System.out.println("圆锥bottom的引用:"+circular.bottom);
    System.out.println("圆锥的体积:"+circular.getVolme());
    System.out.println("修改circle的半径，bottom的半径同样变化");
    circle.setRadius(20);
    System.out.println("bottom的半径:"+circular.getBottomRadius());
     System.out.println("重新创建circle,circular的引用将发生变化");
    circle = new Circle();
    System.out.println("circle的引用:"+circle);
    System.out.println("但是不影响circular的bottom的引用");
    System.out.println("圆锥bottom的的引用:"+circular.bottom);
  }
}
